1. Field
Embodiments of the inventive concept relate to a door mortise lock, and more particularly, to a door mortise lock which may prevent a safety-related accident such as a collision and damage to a lever located in an exterior from occurring when a user suddenly operates the lever by pulling the lever in a state where a dead bolt is not unlocked by enabling a latch bolt to be unlocked in a state where the dead bolt of the door mortise lock is completely unlocked.
2. Description of Related Art
A door lock installed at a door such as a front door includes a mortise that is provided in the door and performs a locking function and levers that are provided in an exterior and an interior of the door in order to operate the mortise.
In general, the mortise includes a latch bolt that operates due to the lever located in the exterior or the interior, a dead bolt that maintains the door in a locked state, and an electromotive or manual driving unit that operates the dead bolt.
When the door is to be opened in the exterior, the door may be opened by operating the dead bolt using a mechanical key, a password, a fingerprint, or the like to unlock the dead bolt and by operating the lever located in the exterior to unlock the latch bolt.
When the door is to be opened in the interior, the door may be opened by operating the dead bolt using an open switch provided in the interior to unlock the dead bolt and by operating the lever located in the interior to unlock the latch bolt.
However, a conventional mortise such as “a mortise that simultaneously unlocks a dead bolt and a latch bolt” disclosed in KR 2009-0067498 has problems of low product safety and low reliability because when a dead bolt and a latch bolt simultaneously operate to unlock the latch bolt, a door lock is easily unlocked, thereby making a user feel uncomfortable.
That is, in the conventional mortise, the latch bolt tends to be unlocked when the user suddenly operates a lever located in an exterior in a state where the dead bolt is not unlocked. In this case, since the dead bolt is not unlocked, when the user pulls the lever, a safety-related accident and damage to the lever may occur.